Lamp and socket therefor



July 29, 1941.

F. R. MEGINNISS LAMP AND SOCKET THEREFOR Filed 0G12. 9, 1937 2Sheets-Sheet 1 www M July 29, 1941.

`F. R. MEGINNlss A LAMP AND SOCKET THEREFOR Filed 001:. 9, 1937 2Sheets-Sheet 2 /Nl/E/v To@ Hana/Ls Meg//s A 7- TOR/VEY Patented July 29,1941 uivirenf STF irais'. Par

7 Claims:`

The-lamp andA socket embodying `my Simeri-1 tion* is more particularly-intended foruse in an atmosphere of explosive gas suchas 'mine gas,

gasoline vapors and thelike, Where explosions are likely toresult -inloss-ofbothilife and-prop-V erty, although it' will be understoodfthatmy inventionis ofgeneral application and is not limitedtoV thisparticular usef One ofv the-most eX plosive gases, and' one' in-which-anincandescent lamp is commonly used; is a mixture 'ofmethaneand'airwhichhas a low critical temperature; At

the same time the operating temperature of the '1 filament 'of atungsten'lamp 'is high," and greatly in' excess of-the critical.temperature of thegas in which it may becused;` In` the case of 'a bulbfracture, V`therefore,` it iis 'highly important that the circuit of`the lamp filament 'bepromptlyopenedand-that the'temperature'ofthefilament be quenched immediately to a point below the ignitiontemperature of the' surrounding gas.

Itfhas heretofore been-proposed"toretain an incandescent lamp intended.fo'r use 'in a rgas of the foregoing character in its socketv by'imeansof a bail attachedftofthe'socket and passing over the end of 'the lamp,-and 'tof provide. a spring ffor ejecting the -larnp from its socket in'case of frac# ture-ofthe bulb. In the 'foregoingconstruction;

however, the Ycontact terminalsincluded'lin the circuit of the lamp havebeen mounted on' springs to bulb fracture and 4this Was-uncertain'asfthe portion of the bail vwhich engages'theY lampbulb' hasbeen formed withreverse'loops'with the re-` sult that the filamentin'its forvfardmovem'ent` was more likely than` not to pass between" theloops of the bail which, in that case would exert noquenchingaction'whateverfon the filament". In accordance -With myinventionfa'movabl'e" element is mounted" on the socketand` isnormallyforced 'into engagement with" the`-bulbof-` the incandescent-lamp,therebyplacing the'bulbunder stress and thefilament of the lamp.is=dis'A posed in the path of movement of the vsaid lelement thelamentengaging portion of which is formed vof a mass of material, preferablymetal,` of good` thermali conductivity and high thermal capacity. Whenthe* lamp is fractured. there-vr fore;V thev said'elementl is broughtinto contact with thelamp lam'ent, thereby quickly quench-v ingritstemperature toia point below the ignition" temperature of.thesurrounding-gases.Y Atthe'fv same-time the said *element.actuat'esior'controls-'i contacts normally? bridging-i a f terminal:contact in the lamp circuit' and the flampcontactg. the-:l`

lsaid' contacts 'being moved outof-bridging rela-VA tion to'the said'terminalsethereby openingzzthe-fz lamp circuit immediatelypon thefracture of thee! bulb and theresulting'f-movement of ftherfsaidfielement. f Y' is the provision of means for promptly opening@y the 'lampcircuit' in` response 'tov lamp --fractureL-1 Another object of my`invention-'is the provisioni of lmeans for promptly quenchingthe'ftemperaw fracture.

Other novel-` features of my 'invention will. ap.-Y pear in "thespecification and Willfbeparticularlyf pointed: out in the claims.

My *invention will best'be understoodby'trefel erence to'theaccompanying drawings' in which@ I have illustrated certain embodimentsthere'ofr and in which- Fig-1 is` a .frontL elevation; partially brokenaway and fin sectionfillustratingfa preferred-em-'- f bodiment of myinvention` in connection vvithan automatic switch used'invconr'iection'vvitha viiash light;

Fig; la is' a front elevation illustrating'- a modii iicationr of myinvention'infwhich the lamp .(not'*k illustrated) Yand socket whichmayfbethe' same as thosefillustratedrin Fig, 1 are associatedwith" aswitch,vv the device being" capable ofuse for 'i `other purposes thanasa ash light.

Fig. 2 is a side vieWof the. lamp;andsocket'v and the associated parts.of Figgl;

Fig. 3 is a'sectional View similar to Fig.. 1 illus.- tratinga` modifiedform of socketfor the recep- A tion-of a lamphavinga plaincylindrical'base.;`Y

Fig. 4 nis a front View, partially. broken-avvay-wl and in section,illustrating my invention i-na de" vice having no inertia switch;

Fig. 5 is aidiagrammatic'- View 'illustrating'ca.-21 modified form of mylnventiom" Fig. 6 isV aiplan viewof YFig.v 5;

Fig. 7 is a View similar to Fig.- 5 illustrating tliy bulbfracturedandthe associated Vpartsfin A-the positions which they assume'onthefracturefofff the bulb;

Fig/8 is a plan view of- Fig. f'7;-

Fig.` 9 iis a diagrammatic f View-'illustrating'arl modification of thelamp terminali;v

Fig. llOvis a'detailed View'.illustrating.;onefofiftheibridgingfcontacts; and; i

OneV of theY objects'off--my invention; therefore,1. y

Fig. 11 is a detailed view illustrating the details of a bridgingcontact of Fig. 5.

Like reference characters indicate like parts throughout the drawings.

Referring to the drawings, and first to Figs. 1 and 2 in which I haveshown my invention embodied in a flash light, III is a fragmentaryportion of the threaded end of the casing of a flash light in which isreceived the threaded base support I I for the lamp and socket embodyingmy invention. The member I I comprises a threaded skirt III which isreceived in the threaded end of the flash light casing, and an inwardlyeX- tending ange I I2 provided with an opening I2 in which is receivedthe lower threaded portion of the lamp socket I3 which is formed with anoutwardly extending annular ange I 4 which engages the upper side of theflange I I 2. In Fig. 1 I have illustrated my invention in connectionwith an inertia operated switch whichmay be of the same or similarcharacter to that shown in my Patent No. 1,948,728, dated February 27,1934, to which reference may be made for further details. The lowerthreaded portion of the socket I3 is received in a metallic sleeve I6surrounding an insulating member I'I in which, in turn, is received thecontact terminal I8 which is included in the lamp circuit. A casing I9for the switch surrounds an insulating member 26 in which the lowerportion of the sleeve I6 is received.

The upper portion of the socket I3 is surrounded by an insulating sleeve2| and this is, in turn, surrounded bya metal sleeve 22 preferably splitand provided at diametrically opposite sides with outwardly extendingspaced flanges 23.

In accordance with my invention a movable element indicated generally at24 is mounted on the lamp socket and comprises two devices similar inconstruction and operation mounted on opposite sides of the lamp 25,each device comprising an arm 26 mounted on a shaft or pintle 26|passing through the flanges 23. The lower portion of the arm 26 mayconveniently be in the form of a yoke which is mounted on the shaft 26|on opposite sides of the flanges 23. 'Ihe upper portion of the arm 26which engages the lamp bulb is formed of a mass of material, preferablymetal, of good thermal conductivity and high thermal capacity and is somounted that the lament of the lamp is in the path of movement of theupper portion of the arm 26. The upper ends of the arms 26 arepreferably ared outwardly in order that the incandescent lamp mayconveniently be inserted, in operative position in the socket withoutthe necessity of manipulating the arms 26. Each device also comprises anarm 29 angular in form and which is pivoted on the shaft or pintle 26|between the flanges 23. The lower inwardly extending portions of thearms 29 pass through openings 21 in the socket I3 and the inner endsthereof are provided with bulbular contact members 36 which when forcedinwardly engage both the contact terminal I8 and the terminal 3| of thelamp to form a bridging connection therebetween.

Resilient means are also provided for simutaneously forcing the bulbengaging portions 23 of the arms 26 into engagement with the lamp bulband forcing the contact bulb 30 into bridging relation between thecontact terminal I8 and the lamp terminal 3|. In the embodiment of myinvention illustrated such means comprises a single spring 32 the upperends of which are spaced.

' minal I8 and the lamp terminal 3| bent inwardly and received inopenings 33 in the two legs of the arms 26 while the lower portionengages the outer lower end of the arm 29, as best indicated in Fig. 2,the spring being so biased as normally to force the arms 26 into contactwith the lamp bulb and to force the lower ends of the arms 29 inwardlyto bring the contacts 30 into bridging relation between the contact ter-Leaf springs 34 are also mounted on the socket and engage the arms 2i)and are biased to force the lower ends of the arms 26 outwardly and tobring the bulbular contacts 36 out of bridging relation between thecontact terminal I8 and the lamp terminal 3| The operation of the deviceillustrated in Figs. 1 and 2 is as follows: In normal operation, thearms 26 engage the lamp bulb 25 in the manner indicated and the contactbulb 30 is maintained in bridging relation between the contact terminalI8 and the lamp terminal 3| In case the bulb is fractured, the arms 26are moved by the springs 32 into engagement with the lamp iilamentthereby quenching the same. When the arms 26 are moved inwardly due tothe bulb fracture, the tensionY in the springs 32 is reducedsufficiently to permit the leaf springs 34 to force the lower ends ofthe spring 32, which are'now under reduced tension, outwardly, therebyopening the lamp circuit between the contact terminal and the lampterminal.

While I have illustrated and described my invention in connection with aflash light, it is to be understood that it is of general application,and when not used in a ilash light the skirt I I I of the supportingbase and the outer portion of the inwardly extending flange I I2 wouldbe omitted, a terminal 35 being connected to the switchv and a secondterminal 35| connected to the supporting base in the manner illustratedin Fig. 1a',

In the embodiment of my invention illustrated in Fig. 3 the inner wallof the lamp socket I3| is plain instead of threaded as in Fig. 1, thelamp being retained in position by the arms 26.

In the embodiment of my invention illustrated in Fig. 4 the socket isused without the inertia operated switch of Fig. 1. Contact screws 352and 353 are connected to the contact terminal I8 and tothe socket |3I,respectively, and the device could be used as a trouble lamp or for anyother desired purpose, it being understood that any suitable'source ofelectric energy and any desired switch would be included in the lampcircuit.

In Figs. 5 to 8 and 11, I have illustrated a modification of myinvention in which the movable element comprises two one-piece arms 36pivotally mounted at 262 on the socket, and having lamp engagingportions as in the arrangement illustrated in Fig. l. On the lower endof each of the arms 36 is mounted a contact member comprising a stem 31passing through an opening 38 in the arm 36 and provided at its innerend with a bulbular contact 36| similar to that shown in Fig. 10. Inorder to provide a yielding contact between the bulbular member 36| andthe contact terminal and the lamp contact, a loose connection isprovided between the arm 36 and the bulb 36|, a spring 39 being in.-terposed between the arm and the bulb. The free end of the stem 3'I ispreferably provided with a head 46 which limits the inward movement ofthe stem. 'Ihe free ends of the members 36 are provided with cross arms4|, the ends of which are connected by springs 42 (Figs. 6 and 8) whichyieldingly force the bulb engaging portions of the arms 36 into yieldingengagement with the bulb. On the fracture of the bulb, the upper ends ofthe arms 3B are forced into engagement with the filament to quench thesame and at the same time the contacts 30! are moved out of engagementwith the contact terminal and with the lamp terminal in the manneralready described in connection with Figs. 1 and 2.

The device embodying my invention overcomes serious defects which havebeen present in certain constructions comprising a bail for opening thelamp circuit when the bulb is fractured. Bails have hitherto been usedwhich were relatively heavy and having little elasticity and which didnot compensate for variations which occur in lamp bulbs. In case thelength of the lamp bulb is in excess of the standard then, the bulb isplaced under a stress and is likely to fracture prematurely. In case thebulb is of less length than the standard, on the other hand, then thelamp is loose and does not make proper contact. In accordance with myinvention, the lamp is at all times forced inwardly by the movableelements which engage the lamp bulb above the maximum diameter.

In Fig. 9 I have illustrated a further modification of my invention forobviating any difficulties which may be due to variations in thicknessof the lamp contact 3| which is usually formed of a drop of solder andthe thickness of which may vary. In the embodiment here illustrated, anadditional contact member 43 is supported on the socket and isinterposed between the contact terminal I8 and the lamp terminal 3|. Acontact terminal 43 of suitable thickness may be installed to producethe desired space between it and the contact terminal I3 and therebycompensate for any variation in thickness in the lamp terminal 3|.

The device embodying my invention opens the lamp circuit immediately andalso promptly quenches the lamp filament in response to the fracture ofthe bulb. It will also be evident that no tools are necessary in theassembly and disassembly of the lamp.

While I have described my invention in its preferred embodiment it is tobe understood that the words which I have used are words of descriptionrather than of limitation and that changes within the purview of theappended claims may be made without departing from the true scope andspirit of my invention in its broadest aspects.

What I claim is:

1. In combination, an incandescent lamp, a socket therefor, a movableelement engageable with the bulb of said lamp, resilient meansassociated with said element for normally forcing the same intoengagement with said bulb, the i'llament of said lamp being disposed inthe path of movement of said element whereby said element moves intoengagement with sai-d filament to quench the same on the fracture ofsaid bulb.

2. In combination, an incandescent lamp, a socket therefor, two armspivotally mounted on said socket and engageable With the bulb of saidlamp on opposite sides and above the maximum diameter thereof, lthelament of said lamp being disposed in the path of movement of said arms,and resilient means for normally forcing said larms into engagement withsaid filament on -the fracture of the lamp bulb.

3. In combination, an incandescent lamp, a socket therefor, a movableelement mounted on said socket and having a bulb engaging portion and anelectrically conducting portion, a contact terminal included in thecircuit of the lamp, means lfor normally forcing said bulb engagingportion of said element into contact with the bulb of said lamp and thecontact portion lthereof into conducting rel-ation between said contactterminal and the lamp terminal, an-d means responsive to the fracture ofsaid bulb for forcing said movable element into engagement with the lampfilament and the conductive portion thereof out of conducting relationto said terminals.

4. In a device of the character described, an incandescent lamp, asocket therefor, a movable quenching element pivotally mounted on saidsocket, a contact terminal loc-ated adjacent to and spaced from the lampterminal, a terminal bridging element pivotally mounted on the same axisas said quenching element, a common means for forcing said quenchingelement into contact with the lamp bulb and said bridging element intoconducting bridging relation between said contact terminal and the lampterminal, and means responsive to the fracture of the light bulb formoving said bridging elem-ent out of bridging relation between saidcontact terminal and said lamp terminal.

5. In a device of the character described, an incandescent lamp, asocket therefor, a movable quenching element pivotally mounted on saidsocket, the lamp filament being disposed in the path of movement of-said element, a contact terminal located adjacent to and spaced fromthe lamp terminal, a terminal bridging element pivotally mounted on thesame axis as said quenching element, a common means for forcing saidquenching element into contact with the lamp bulb and said bridgingelement into conducting bridging relation between said contact terminaland the lamp terminal, and means responsive to the fracture of the lightbulb .for moving said bridging element out of bridging relation betweensaid contact terminal and said lamp terminal and said movable `elementinto contact with the lamp filament.

6. A device of the character described, including a socket adapted toreceive the base of an electric lamp, a movable member having a portionadapted to engage the bulb of a lamp held in said socket, spring meansfor holding said member in contact with the lamp bulb and adapted tomove said member upon the breaking of the bulb of .the lamp, contactmembers included in an electric circuit through said lamp, one of whichis movable with said movable member, and adapted to be disengaged from acooperating contact member upon -the breaking of the bulb of said lampto open the circuit of said lamp.

'7. A device of the character described, including a screw socket intowhich the base of an electric lamp is adapted to be screwed to bestationarily held therein, a movable member having a portion adapted toengage the bulb of a lamp held in said socket, spring means for holdin-gsaid movable member in contact with the lamp bulb and adapted to movesaid member upon the breaking of the bulb of the lamp, circuit contactmembers included in an electric circuit through sai-d lamp, one of saidcontact members being movable with said movable member and adapted to bedisengaged from a co-operating contact member upon Athe breaking of thebulb of said lamp to open the circuit of said lamp.

FRANCIS R. MEGINNISS.

